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Posted: Fri 4th Jul 2025
Last updated: Fri 4th Jul 2025
5 min read
If you're newly self-employed or starting a small business, you'll need a UTR number.
And if you need information on UTR numbers, you're in the right place. Discover what they are, what they look like and why you need one for your taxes.
UTR means 'Unique Taxpayer Reference' and is a number you get from Her Majesty's Revenue & Customs (HMRC). If you're employed by someone else, you don't need a UTR.
But if you're entering self-employment with a view to completing any financial transactions – which you'd certainly hope! – you'll need one to track your yearly tax records.
Also known as ‘tax references', UTRs are 10 digits long and sometimes include a letter 'K' at the end. Once you get your UTR number, it stays the same for life.
You'll only need a UTR number if you submit a Self Assessment tax return form.
Without a valid UTR number, your self-assessment tax return won't be submitted correctly and this can result in a potential fine, so waste no time in getting on top of this.
Individuals who need to file a tax return include those who:
are self-employed or freelance
own a limited company
earned over £100,000
owe any tax on savings, dividends or capital gains
earned over £10,000 from savings interest or investment income
earned £2,500 or more in untaxed income such as commission
A UTR number helps HMRC identify and track your tax records. This in turn helps them keep tabs on your tax obligations by working out your annual income tax and National Insurance contributions.
Collaborating with an accountant can be a great way to guarantee that your monetary matters are properly organised.
Experienced accountants have a thorough comprehension of tax legislation and can offer helpful advice on how you can increase your savings and lessen your liabilities. Furthermore, they can help you formulate a budget, handle investments and plan for retirement.
When joining forces with an accountant, you must make sure they have the proper credentials and background to manage your finances. You should also grant them your Unique Taxpayer Reference (UTR) figure so they can access the related data about you from HMRC.
This will allow them to measure up your monetary circumstances and guide you accordingly. Also, enlisting an accountant will give you a sense of serenity knowing that all of your financial matters are being settled professionally and competently.
Your journey into self-employment starts with registering for self-assessment with HMRC. You can register:
online at the HMRC website
by telephone on 0300 200 3310
by post at: Pay As You Earn and Self Assessment, HM Revenue & Customs, BX9 1AS
To speed up the process, you'll need the following details to hand:
Your full name
A current address
An email address
Date of birth
Phone number
It can take up to seven days for your UTR to arrive, but when it does it'll come by post and will arrive at your business address. You'll receive a letter titled Welcome to Self Assessment, which will have your tax reference on it.
If you've lost or can't find your UTR number, it will be on a previous tax return or your Welcome to Self Assessment letter. It'll also be on payment reminders or bank statements.
HMRC can provide a replacement UTR for limited company directors who have misplaced theirs.
If you submit a paper tax return, your UTR is on the first page, just above your National Insurance number. For online tax returns, your UTR is on the second page below your last name and above your National Insurance number.
Corporation or company tax UTRs are references used by businesses instead of individuals.
HMRC issues corporation tax UTRs to all limited companies registered with Companies House. Because personal UTRs are only issued to self-employed people, they can't replace a corporation UTR.
It is possible to have both a personal and corporation tax UTR as long as both 'companies' are kept separate.
